1. Field of the Invention
The present invention relates generally to a bead and apex for a vehicle tire. In particular, the present invention relates to a bead and apex formed as an integral unit and to a method for making a tire incorporating such integral bead and apex unit.
2. Description of the Prior Art
A bead and an apex for use in the construction of a vehicle tire are known. For example, U.S. Pat. No. 1,809,106 discloses a bead ribbon having a bead portion with rubber located about parallel extending bead wires. A strip of rubber extends laterally outwardly and upwardly from one edge of the bead portion. The bead ribbon is wound spirally about itself a plurality of times to form a bead core ring. The bead core ring is placed around a carcass ply that is supported on a drum in a cylindrical form. The rubber strips extend axially inward along the carcass ply. The end of the carcass ply is then turned over the bead core ring. The assembly is then removed from the drum. When the assembly is shaped into its a toroidal form of a finished tire, the entire bead core ring is turned 90 degrees. The agglomeration of rubber formed by the rubber strips extend from the same surface of the bead portion that the rubber strips extended from originally. However, the agglomeration now forms a radially oriented apex.
U.S. Pat. No. 4,168,193 discloses forming a wire bead ring. The bead ring is then placed in a mold. A cavity in the mold is injected with unvulcanized rubber to form a bead assembly with an apex portion extending substantially radially of the bead ring.
Bead and apex assemblies, such as those referenced above, have certain disadvantages. For example, a bead that is typically used today is substantially inextensible and is extremely difficult to turn through a 90 degree angle. In fact, modern radial tire building operations and machines have been adapted to accept the relatively inextensible beads which are not turned any appreciable amount during construction of a vehicle tire. Furthermore, injecting uncured rubber about a bead ring requires an additional manufacturing step, additional handling and additional capital equipment in the form of the injection molding apparatus. All of these additions can be costly to the forming of an apexed bead.